Mitsubishi QCPU (Q Mode), Руководство пользователя

Страница: 297 / 456

10 - 50 10 - 50
MELSEC-Q
10 DEVICES
10.7.5 Precautions in using file registers
(1) Using file register Nos. not registered or outside the registered
range
(a) When file register files are not registered in the High Performance model
QCPU, no error occurs even if reading/writing to file registers
Reading data from a file register results in the following:
• Undefined data is stored in the standard RAM.
• "0
H
" is stored in a memory card.
(b) Writing/reading file register Nos. outside the registered range (points)
No error occurs even if reading/writing occurs to these file registers.
Reading data from a file register results in the following:
• Undefined data is stored in the standard RAM.
• "0
H
" is stored in a memory card.
(2) File register capacity check
(a) Perform a file register capacity check in the sequence program, so that
reading/writing from/to the file register is performed within the size (number
of points) set in the High Performance model QCPU.
• A file register capacity check should be executed at step 0 of programs in
which file registers are used.
• After switching to another file register file using the QDRSET instruction,
execute a file register capacity check.
• When using the RSET instruction to switch blocks, confirm that the
switching destination block has a capacity of 1k points or more before
executing the RSET instruction.
(File register capacity) > [32k points (switching block No.) + 1k points]
(b) The available file register capacity can be checked in the file register
capacity storage register (SD 647). 1
The file register capacity is stored in SD647 in 1k point units.
The "less than 1k points" surplus portion of a file register
capacity is not stored.
In order to ensure an accurate "range of use" check, be sure
to designate the file register setting in 1k point (1024 points)
units.
REMARK
1 : If a file register file is switched to another, the file register capacity of the
currently selected file register file is stored in SD647.